The following relates generally to memory devices and more specifically to efficient utilization of die area for three-dimensional cross-point architecture.
Memory devices are widely used to store information in various electronic devices such as computers, wireless communication devices, cameras, digital displays, and the like. Information is stored by programming different states of a memory device. For example, binary devices have two states, often denoted by a logic “1” or a logic “0.” In other systems, more than two states may be stored. To access the stored information, the electronic device may read, or sense, the stored state in the memory device. To store information, the electronic device may write, or program, the state in the memory device.
Multiple types of memory devices exist, including magnetic hard disks, random access memory (RAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), read only memory (ROM), flash memory, phase change memory (PCM), and others. Memory devices may be volatile or non-volatile. Non-volatile memory, e.g., FeRAM and PCM, may maintain their stored logic state for extended periods of time even in the absence of an external power source. Volatile memory devices, e.g., DRAM, may lose their stored state over time unless they are periodically refreshed by an external power source. Improving memory devices may include increasing memory cell density, increasing read/write speeds, increasing reliability, increasing data retention, reducing power consumption, or reducing manufacturing costs, among other metrics.
FeRAM may use similar device architectures as volatile memory but may have non-volatile properties due to the use of a ferroelectric capacitor as a storage device. FeRAM devices may thus have improved performance compared to other non-volatile and volatile memory devices. PCM or chalcogenide-material-based memories may be non-volatile and may offer improved read/write speeds and endurance compared to other memory devices. PCM or chalcogenide-material-based memories may also offer increased memory cell density capabilities. For example, three-dimensional memory arrays employing FeRAM, PCM, or chalcogenide-material-based memories may be possible. However, in some three-dimensional architectures, regions of the memory device may be dedicated to support circuitry and may be exclusive of memory cells. Such areas may increase the physical dimensions of the memory device without increasing the capacity of the memory device.